First, cook the chicken. While cooking, put the frozen peppers and onions in a bowl of water. Heat them for 1 minute in the microwave. Drain the water.
Once chicken is cooked, shred the breasts. Pour chicken in the bowl with the onions and peppers. Add in salsa, chicken broth, and taco seasoning. Combine well.
Spoon the chicken in the burrito shells. Divide the chicken evenly. Next, fold the shells, and place them in a 9x13 baking dish.
Preheat the oven at 350 degrees.
In a saucepan over medium heat, melt the salted butter. As it melts, use a whisk to stir in the flour.
Once combined, add the chicken broth, and stir with the whisk. Let it simmer for 2 minutes.
Stir in the sour cream. Once combined, add 2 cups of cheese to the sauce.
Once the cheese is melted, pour the sauce over the chicken enchiladas in the baking dish. Sprinkled the remaining one cup of cheese over the enchiladas.
Place pan in the oven for 25 minutes or until the sauce is bubbling.
Let cool slightly before serving. Enjoy!